Systems, methods and tools for distributing different pluralities of abrasive particles to make abrasive articles

ABSTRACT

A system includes a distribution tool, a backing, a first plurality of abrasive particles and a second plurality of abrasive articles. The distribution tool includes a first section and a second section. The first section is configured to receive the first plurality of abrasive particles and pass the first plurality of abrasive particles through one or more of the plurality of slots to the backing. The second plurality of abrasive particles differ in at least one of a size, an average weight and a shape from the first plurality of abrasive particles. The second section is configured to receive the second plurality of abrasive particles and pass the second plurality of abrasive particles through one or more of the plurality of slots to the backing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. 371 ofPCT/US2017/066706, filed Dec. 15, 2017, which claims the benefit of U.S.Provisional Application No. 62/437,307, filed Dec. 21, 2016, thedisclosures of which incorporated by reference in their entiretiesherein.

BACKGROUND

The present disclosure relates generally to abrasive articles, and also,to tools, systems and methods for arranging abrasive particles on abacking as part of the manufacture of an abrasive article. In general,coated abrasive articles have an abrasive layer secured to a backing.The abrasive layer comprises abrasive particles and a binder thatsecures the abrasive particles to the backing. One common type of coatedabrasive article has an abrasive layer comprised of a make coat orlayer, a size coat or layer, and abrasive particles. In making such acoated abrasive article, a make layer precursor comprising a curablemake resin is applied to a major surface of the backing. Abrasiveparticles are then at least partially embedded into the curable makeresin, and the curable make resin is at least partially cured to adherethe abrasive particles to the major surface of the backing. A size layerprecursor comprising a curable size resin is then applied over the atleast partially cured curable make resin and abrasive particles,followed by curing of the curable size resin precursor, and optionallyfurther curing of the curable make resin.

Application of the abrasive particles to a major face of a backingconstruction (e.g., a backing coated with a make layer precursor) isoftentimes accomplished via drop coating technique in which a bulksupply of the abrasive particles are fed through a hopper and fall ontothe major face (e.g., onto or into the make layer precursor) under theforce of gravity. A spatial orientation of the abrasive particles uponcontacting the major face is entirely random in all directions.Alternatively, electrostatic coating (e-coat) is also well known, andgenerally employs an electrostatic field to propel the abrasiveparticles vertically against the force of gravity onto the major face(e.g., onto or into the make layer precursor). With electrostaticcoating, it is possible to effect the orientation of the abrasiveparticles in one direction such that each abrasive particle's elongateddimension is substantially erect (standing up) with respect to thebacking surface. However, electrostatic coating is more expensive thandrop coating, and may not be viable with all types of abrasive particles(e.g., it can be difficult to consistently electrostatically coatrelatively large abrasive particles).

In light of the above, a need exists for improved systems and methodsfor applying abrasive particles to a backing construction as part of themanufacture of an abrasive article.

SUMMARY

Aspects of the present disclosure are directed toward a method of makingan abrasive article. The method can include: loading a first pluralityof abrasive particles and a second plurality of abrasive particles to adistribution tool, the distribution tool has a first section forreceiving the first plurality of abrasive particles and a second sectionfor receiving the second plurality of abrasive particles, the firstsection and the second section each including a plurality of wallsdefining a plurality of slots, each of the plurality of slots being opento a lower side of the distribution tool, wherein the first plurality ofabrasive particles differ in at least one of a size, an average weightand a shape from the second plurality of abrasive particles;distributing the first plurality of abrasive particles from the firstsection of the distribution tool on to a first major face of a backinglocated immediately below the lower side of the distribution tool andmoving relative to the distribution tool; distributing the secondplurality of abrasive particles from the second section of thedistribution tool on to the first major face of the backing locatedimmediately below the lower side of the distribution tool and movingrelative to the distribution tool; wherein the first plurality ofabrasive particles and the second plurality of abrasive particles whendistributed on the backing extend in similar paths in a down-webdirection of the backing, the similar paths are limited to a cross-webrange defined by the plurality of walls.

The present disclosure includes a system for making an abrasive article.The system can include a distribution tool, a backing, a first pluralityof abrasive particles and a second plurality of abrasive articles. Thedistribution tool includes a first section and a second section. Each ofthe first section and second section having a plurality of wallsdefining a plurality of slots. Each of the slots being open to a lowerside of the distribution tool. The backing is configured to be disposedimmediately adjacent the lower side of the distribution tool. The firstsection is configured to receive the first plurality of abrasiveparticles and pass the first plurality of abrasive particles through oneor more of the plurality of slots to the backing. The second pluralityof abrasive particles differ in at least one of a size, an averageweight, chemistry and a shape from the first plurality of abrasiveparticles. The second section is configured to receive the secondplurality of abrasive particles and pass the second plurality ofabrasive particles through one or more of the plurality of slots to thebacking.

The present disclosure provides an abrasive article having a y-axis, anx-axis transverse to the y-axis, and a z-axis orthogonal to the y-axisand x-axis. The abrasive article can comprise a first plurality ofabrasive particles and a second plurality of abrasive particles. Thefirst plurality of abrasive particles differ in at least one of a size,an average weight, chemistry and a shape from the second plurality ofabrasive particles. The first plurality of abrasive particles can bespaced from the second plurality of abrasive particles by at least aminimum distance in the x-axis direction. Both the first plurality ofabrasive particles and the second plurality of abrasive particles extendin similar paths to one another with respect to the y-axis.

According to another example embodiment, a coated abrasive article isprovided. The coated abrasive article comprises: a backing, a make coatand a plurality of abrasive particles. The backing can have opposedfirst and second major surfaces, as well as, a longitudinal axis and atransverse axis. The make coat can be disposed on at least a portion ofone of the first and second major surfaces. The plurality of abrasiveparticles can be secured to the backing via the make coat. The pluralityof abrasive particles can comprise a first plurality of abrasiveparticles and a second plurality of abrasive particles. The firstplurality of abrasive particles can differ in at least one of a size, anaverage weight, chemistry and a shape from the second plurality ofabrasive particles. The first plurality of abrasive particles can bespaced from the second plurality of abrasive particles by at least aminimum distance in the transverse axis direction. Both the firstplurality of abrasive particles and the second plurality of abrasiveparticles can extend in similar paths to one another with respect to thelongitudinal axis direction.

In another embodiment, an abrasive disc is disclosed. The abrasive disccan have a backing having opposed first and second major surfaces, aradial axis, an annular path, and a z-axis orthogonal to at least one ofthe first and second major surfaces. The abrasive disc can have a makecoat on at least one of the first and second major surfaces.Additionally the abrasive disc can have a plurality of abrasiveparticles secured to the backing via the make coat. The plurality ofabrasive particles can comprise a first plurality of abrasive particlesand a second plurality of abrasive particles. The first plurality ofabrasive particles can differ in at least one of a size, an averageweight, chemistry and a shape from the second plurality of abrasiveparticles. The first plurality of abrasive particles can be spaced fromthe second plurality of abrasive particles by at least a minimumdistance in the radial axis direction. Both the first plurality ofabrasive particles and the second plurality of abrasive particles canextend in similar paths to one another with respect to the annular pathdirection.

As used herein, the following terms may have the following meaning:

“Length” refers to the maximum caliper dimension of an object.

“Width” refers to the maximum caliper dimension of an objectperpendicular to the length axis.

The term “thickness” refers to the caliper dimension of an object thatis perpendicular to the length and width dimensions.

The term “caliper dimension” is defined as the distance between the twoparallel planes restricting the object perpendicular to that direction.

The term “platey abrasive particle” and particles described as having a“plate-like shape” refer to an abrasive particle resembling a plateletand/or flake that is characterized by a thickness that is less than thelength and width. For example, the thickness may be less than ½, ⅓, ¼,⅕, ⅙, 1/7, ⅛, 1/9, or even less than 1/10 of the length and/or width.

The term “crushed abrasive particle” refers to an abrasive particle thatis formed through a fracturing process such as a mechanical fracturingprocess. The material fractured to produce the crushed abrasive particlemay be in the form of bulk abrasive or an abrasive precursor. It mayalso be in the form of an extruded rod or other profile or an extrudedor otherwise formed sheet of abrasive or abrasive precursor. Mechanicalfracturing includes, for example, roll or jaw crushing as well asfracture by explosive comminution.

The term “shaped abrasive particle” refers to a ceramic abrasiveparticle with at least a portion of the abrasive particle having apredetermined shape that is replicated from a mold cavity used to form aprecursor shaped abrasive particle which is sintered to form the shapedabrasive particle. Except in the case of abrasive shards (e.g., asdescribed in U.S. Pat. No. 8,034,137 B2 (Erickson et al.)), the shapedabrasive particle will generally have a predetermined geometric shapethat substantially replicates the mold cavity that was used to form theshaped abrasive particle. The term “shaped abrasive particle” as usedherein excludes abrasive particles obtained by a mechanical crushingoperation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified illustration of a portion of a system formanufacturing abrasive articles in accordance with principles of thepresent disclosure, the system including a distribution tool.

FIG. 2A is a top plan view of a triangular abrasive particle useful withthe tools, systems, and methods of the present disclosure.

FIG. 2B is an end view of the triangular abrasive particle of FIG. 2Ashowing a thickness of the particle.

FIG. 2C is a side view of the triangular abrasive particle of FIG. 2Ashowing a height of the particle.

FIG. 3 is a perspective view of one embodiment of the distribution toolreceiving differently shaped abrasive particles for disposition on abacking.

FIG. 4 is a perspective view of another embodiment of the distributiontool receiving different types of abrasive particles, the differenttypes of abrasive articles selectively partitioned by the distributiontool to be arranged in distinct rows according to particle type on thebacking.

FIG. 4A is an enlargement of a portion of the distribution tool of FIG.4.

FIG. 5 is a cross-section taken in a cross-web direction of anotherembodiment of the distribution tool receiving abrasive particles, thedistribution tool having walls and slots that orient the abrasiveparticles to fall with a minor surface disposed on the backing.

FIG. 6A is a side view of the abrasive particle of FIGS. 2A-2C.

FIG. 6B is a side view of the distribution tool of FIG. 5 interactingwith the abrasive particle of FIG. 6A as part of a system and method formanufacturing abrasive articles.

FIG. 6C is the arrangement of FIG. 6B at a later point in themanufacturing method.

FIG. 6D is an end view of the arrangement of FIG. 6B.

FIG. 7 is a simplified top view illustrating a method of manufacturingan abrasive article using a distribution tool in accordance with anexample of the present disclosure.

FIG. 8 is a perspective view of another embodiment of a distributiontool that is used as part of a method and system for manufacturingabrasive articles according to another example of the presentdisclosure.

FIGS. 8A and 8B are simplified views from various perspectives ofsegments of the distribution tool of FIG. 8 with portions removed.

FIG. 9 is a simplified view of another embodiment of the distributiontool similar to the embodiment of FIGS. 8-8B save that one drum of thedistribution tool is spaced form the backing.

FIG. 10A is a top view of a first abrasive article having the firstplurality of abrasive particles and the second plurality of abrasiveparticles, the first plurality of abrasive particles spaced from thesecond plurality of abrasive particles in an x-direction (e.g.,corresponding to a cross-web direction).

FIG. 10B is a top view of a second abrasive article shaped a disc havingthe first plurality of abrasive particles and the second plurality ofabrasive particles according to another embodiment of the presentdisclosure.

FIG. 11 shows the first plurality of abrasive particles and the secondplurality of abrasive particles as shaped abrasive particles disposed ona backing according to yet another embodiment of the present disclosure.

FIG. 11A is a digital image of shaped abrasive particles having adisposition on the backing similar to that of the embodiment of FIG. 11.

FIG. 12 shows the first plurality of abrasive particles as shapedabrasive particles and the second plurality of abrasive particles ascrushed abrasive particles disposed on a backing according to yetanother embodiment of the present disclosure.

FIG. 12A is a digital image of shaped abrasive particles and crushedabrasive particles having a disposition on the backing similar to thatof the embodiment of FIG. 12.

DETAILED DESCRIPTION

Aspects of the present disclosure relate to abrasive articles, tools,systems and methods for manufacturing abrasive articles with a backingconstruction. As a point of reference, FIG. 1 illustrates portions of asystem 20 for manufacturing abrasive articles in accordance withprinciples of the present disclosure, including a distribution device 22along with other components or devices commonly employed in themanufacture of abrasive articles. For example, the manufacture ofabrasive articles conventionally includes structures and mechanisms(e.g., rollers, conveyor belts, etc.) for moving a backing constructionweb 24 along a path of travel or machine direction 26. The backingconstruction web 24 can assume various forms, and in some embodimentsincludes a backing 28 to which a make coat precursor resin 30 (or otherresin or adhesive) has been applied. For example, with the non-limitingarrangement of FIG. 1, the backing 28 is advanced past a coater 32 thatapplies the make coat precursor resin 30 on a major surface 34 of thebacking 28 thereby creating the backing construction web 24 (e.g., acoated backing). In other embodiments, multiple coatings can be appliedto the backing 28 to generate the backing construction web 24 asdelivered to the distribution tool 22; in yet other embodiments, thebacking construction web 24 consists of the backing 28 alone (i.e.,prior to interacting with the distribution device 22, the backing 28 isnot subjected to a resin coating operation). Abrasive particles 36A and36B (a size of which is greatly exaggerated in FIG. 1 for ease ofunderstanding) are applied to a major face 38 of the backingconstruction web 24 by the distribution device 22 that otherwisedistributes the abrasive particles 36A and 36B from supply 40A andsupply 40B, respectively, as described below. After application of theabrasive particles 36, the backing construction web 24 exits thedistribution device 22 and is optionally subjected to further processing(e.g., application of a size coat 42, application of additional abrasiveparticles by conventional means (e.g., e-coat), application of agrinding aid, application of a supersize coat, curing, cutting, etc.),such as from device 43, to produce a final abrasive article, such as acoated abrasive article.

As shown in FIG. 1, the abrasive particles 36A and 36B can be of adifferent type with respect to one another. Indeed, according to someembodiments, the abrasive particles 36A and 36B can have one or more ofa different size, shape, chemistry, and/or average weight from oneanother.

Supplies 40A and/or 40B can be positioned a height H above thedistribution device 22. The magnitude of height H can affect theefficiency with which particles are received in the distribution device22. For example, sometimes particles can impact distribution device 22after passing out of supply 40 and can bounce out of distribution device22 if dropped from too great a height H. These particles are either lostfrom system 20, thereby producing waste, or land on major face 38 andcan result in improperly aligned particles that can potentially decreasethe abrasive efficiency of the coated abrasive article. Thus, it hasbeen found that fewer particles 36A or 36B can be lost from distributiondevice 22 if supply 40 is brought closer to distribution device 22. Inparticular, bringing supply 40 closer to distribution device 22 canreduce the linear momentum of the particles, thereby reducing theirspeed upon contact with distribution device 22. This can lower thereactive impact force on the particle, which can reduce the particlesfrom “jumping out” of distribution device 22. In other examples, themass of the particles can be decreased to reduce the linear momentum ofthe particles or the height H can be adjusted as desired in view of themass of the particles to reduce the linear momentum of the particles.

The distribution device 22 is configured to effectuate gross biasedorientation and alignment of at least a majority of the abrasiveparticles 36A and 36B as applied and subsequently bonded to the majorface 38. With this in mind, portions of embodiments of the distribution(also referred to herein as a distribution tool) are shown in shown infurther detail in subsequent FIGURES.

The distribution devices 22 disclosed can utilize different types ofabrasive particles, for example a first plurality of abrasive particlesand a second plurality of abrasive particles. These particles can befeed to the distribution device from different supplies (e.g. supply 36Aand supply 36B). These particles can be conveyed to different areas ofthe distribution device and can fall on different areas of the backingin either or both of an up-web/down-web location and a cross-weblocation. For example, in the embodiment of FIG. 3, a first plurality ofabrasive particles of a first type are dropped to the distributiondevice up-web of a second plurality of abrasive particles of a secondtype. Such configuration allows for alternating or variation of particletype in a down-web direction (also referred to herein as a longitudinalaxis direction, longitudinal direction or y-axis direction). In theembodiment of FIGS. 4-4A, a first plurality of abrasive particles of afirst type are dropped to the distribution device up-web and cross-webof a second plurality of abrasive particles of a second type. Thisallows for alternating or variation of particle type in a cross-webdirection (also referred to herein as a transverse axis direction,transverse direction or x-axis direction).

FIG. 2A is a plan view of a triangular abrasive particle 100 showing amajor surface 102 thereof. FIG. 12B is an end view of the triangularabrasive particle 100 of FIG. 12A showing a thickness of the particle100 in a minor surface 106. FIG. 12C is a side view of the triangularabrasive particle 100 of FIG. 12A showing a height of the particle aswell as another minor surface 110.

The abrasive particles are described herein by way of example and canhave various configurations. For example, the abrasive particles can beconstructed of various materials including but not limited to ceramics,metal alloys, composites or the like. Similarly, the abrasive particlescan be substantially entirely constructed of one material, can havecoatings on portions thereof, or can have layers on one or more surfacesthereof according to some examples. The abrasive particles can be shapedabrasive particles (e.g., FIGS. 2A-2C) according to some examples.According to other examples the abrasive particles can comprise crushedparticles, crush grains, agglomerates, or the like. Magnetizableabrasive particles can be used in loose form (e.g., free-flowing or in aslurry) or they can be incorporated into various abrasive articles aswill be discussed subsequently.

The body of the abrasive particle can be shaped (e.g., precisely-shaped)or random (e.g., crushed). Shaped abrasive particles andprecisely-shaped ceramic bodies can be prepared by a molding processusing sol-gel technology as described in U.S. Pat. No. 5,201,916 (Berg);U.S. Pat. No. 5,366,523 (Rowenhorst (Re 35,570)); and U.S. Pat. No.5,984,988 (Berg). U.S. Pat. No. 8,034,137 (Erickson et al.) describesalumina particles that have been formed in a specific shape, thencrushed to form shards that retain a portion of their original shapefeatures. In some embodiments, the ceramic bodies are precisely-shaped(i.e., the ceramic bodies have shapes that are at least partiallydetermined by the shapes of cavities in a production tool used to makethem).

Exemplary shapes of ceramic bodies include crushed, pyramids (e.g., 3-,4-, 5-, or 6-sided pyramids), truncated pyramids (e.g., 3-, 4-, 5-, or6-sided truncated pyramids), cones, truncated cones, rods (e.g.,cylindrical, vermiform), and prisms (e.g., 3-, 4-, 5-, or 6-sidedprisms).

The abrasive particles can have any size, but can be much smaller thanthe ceramic bodies as judged by average particle diameter, in yet othercases 4 to 2000 times smaller, in yet other cases 100 to 2000 timessmaller, and in yet other cases 500 to 2000 times smaller, althoughother sizes can also be used. In this embodiment, the particles can havea Mohs hardness of 6 or less (e.g., 5 or less, or 4 or less), althoughthis is not a requirement.

The gross biased orientation and alignment provided by distributiontools of the present disclosure can be characterized by reference tomajor axes and dimensions of the abrasive particles. FIGS. 2A-2C show ageneric, non-limiting example of the abrasive particle 100, the exteriorshape of which defines a particle maximum length, maximum height andmaximum thickness L_(P), H_(P), T_(P) dimensions that represent maximumdimensions of the abrasive particles 100 in three orthogonal planes. Theparticle maximum length, height and thickness L_(P), H_(P), T_(P) are afunction of a shape of the abrasive particle 100, and the shape may ormay not be uniform. The present disclosure is in no way limited to anyparticular abrasive particle shape, dimensions, type, etc. However, withsome shapes the “height” of the abrasive particle 100 may moreconventionally be referred to as a “width”.

The abrasive particle 100 is shown in FIGS. 2A-2C as arbitrarily havinga triangle shape, with opposing major surfaces 202, 204 (one of which isvisible in FIG. 2A) and opposing minor surfaces 206, 208 and 210(sometimes referred to as side faces herein). Regardless of an exactshape, any abrasive particle can be described as providing the particlemaximum length L_(P) as the largest dimension in any one plane, theparticle maximum height H_(P) as being the largest dimension in anyplane orthogonal to the plane of the maximum length L_(P), and themaximum thickness T_(P) as being the largest dimension in a third planeorthogonal to the planes of the maximum length L_(P) and height H_(P).The particle maximum length L_(P) is greater than or equal to theparticle maximum height H_(P), and the particle maximum height H_(P) isgreater than or equal to the particle maximum thickness T_(P). Abrasiveparticles useful with the present disclosure can have circular orspherical geometries such that the terms “length”, “height” or“thickness” are inclusive of diameter.

A shape of the abrasive particle 100 is akin to an equilateraltriangular prism. Due to the equilateral triangular prism shape, themaximum length L_(P) and the maximum height H_(P) are not uniform acrossa thickness of the abrasive particle 100 (i.e., the abrasive particle100 can be viewed as defining opposing major surfaces 102, 104; themaximum length and height L_(P), H_(P) exist at both of the surfaces102, 104). The maximum height H_(P1) is known or can be calculated, andcan equal the maximum length L_(P). The maximum thickness T_(P) is lessthan the maximum length and height L_(P), H_(P). Minor surfaces faces106, 108, and 110 of the abrasive particle 100 have an identical shapeand size, and are perpendicular to the major surfaces 102, 104.

A shape of the abrasive particle 100 defines a centroid at whichparticle X_(P), Y_(P) and Z_(P) axes can be defined (the particle X_(P),Y_(P) and Z_(P) axes are orthogonal relative to one another). With theconventions of FIG. 2A-2C, the particle Z_(P) axis is parallel with themaximum height H_(P), the Y_(P) axis is parallel with the maximum lengthL_(P), and the X_(P) axis is parallel with the maximum thickness T_(P).As a point of reference, the particle X_(P), Y_(P), Z_(P) axes areidentified for the abrasive particle 100 as a standalone objectindependent of the backing construction web 24 (FIG. 1); once applied tothe backing construction web 24, a “z-axis rotation orientation” of theabrasive particle 100 is defined by the particle's angular rotationabout a z-axis passing through the particle and through the backing towhich the particle is attached at a 90 degree angle to the backing.Similarly, a “y-axis orientation” of the abrasive particle 100 isdefined by the particle's disposition relative to a y-axis passingthrough the particle and along the backing to which the particle isattached. As discussed previously, a corresponding y-axis of the articlecan comprise the longitudinal axis and an up-web/down-web axis (ordirection) if the backing is being manufactured on a web as described inseveral of the exemplary embodiments. An “x-axis orientation” of theabrasive particle 100 is defined by the particle's disposition relativeto an x-axis passing through the particle and along the backing to whichthe particle is attached. As discussed previously, a correspondingx-axis of the article can comprise the transverse axis and cross-webaxis (or direction) if the backing is being manufactured on a web asdescribed in several of the exemplary embodiments.

The gross biased orientation effected by the distribution tools of thepresent disclosure entail dictating or limiting a spatial arrangement ofthe abrasive particle to a range of rotational orientations about theparticle Z_(P) axis and to a range of rotational orientations about theparticle Y_(P) axis; the gross biased orientation does not dictate orlimit a rotational orientation about the particle X_(P) axis. Forexample, FIG. 6D shows the abrasive particles of two different typesbeing received within one of the respective slots of the distributiontool 300. The opposing walls 314 that define the slot limit a rotationalorientation of the abrasive particles 101 c, 101 d and 101 e (shapedabrasive particle) about the Z_(P) axis to a limited range oforientations. Similarly, in FIG. 6D the abrasive particles gross biasedorientation includes the opposing walls 314 limiting a rotationalorientation of the abrasive particles 101 c, 101 d and 101 e about theY_(P) axis within a limited range or orientations. Finally, FIG. 6B is aside view of the abrasive particle 100 within the slot 316 (referencedgenerally). As shown in FIG. 6B, the abrasive particles 100 can freelyassume any rotational orientation about the X_(P) axis (however oncepassed through the distribution tools the backing can limit therotational orientation about the X_(P) axis.

Furthermore, the distribution tools of the present disclosure can limitthe spatial arrangement of the abrasive particles relative to oneanother on the backing in at least the cross-web direction. For example,FIG. 6D shows the abrasive particles 101 c, 101 d and 101 e as well asparticles of two different types being received within one of therespective slots of the distribution tool 300. The opposing walls 314that define the slot 204 limit the cross-web disposition of the abrasiveparticles relative to one another. Thus, the abrasive particles aredisposed at least a minimum distance (dmin) from one another as dictatedby the thickness of the walls so as to be segregated from one another inthe cross-web direction. The arrangement of particles arranged bydifferent particle type and spaced a distance apart so as to formdistinctive rows is further illustrated in FIGS. 10A and 10B.

With the above general explanations in mind, it should be noted thatdimensions of the walls and the slots for each distribution tool areselected as a function of expected geometry or dimensions of theabrasive particles to be processed. In more general terms, thedimensions of the walls and the slots are selected based upon theexpected particle maximum length L_(P), maximum height H_(P), andmaximum thickness T_(P) of the abrasive particles to be processed (itbeing understood that a bulk supply of a particular abrasive particlewill purport to contain identically sized and shaped abrasive particles;invariably, however, individual ones of the abrasive particles withinthe bulk supply will have dimensions that slightly vary from one anotherwithin an accepted tolerances; thus, when selecting dimensions for therespective walls and the slots for distributing the abrasive particlesof the bulk supply as described in the present disclosure, the“dimensions” of any one abrasive particle of the bulk supply can be withreference to nominal dimension of the bulk supply).

Dimensions of the walls and the slots are generally configured such thatthe slot width W_(S) (FIG. 3) is less than at least the abrasiveparticle maximum length L_(P), and optionally less than the abrasiveparticle maximum height H_(P), dictating that the abrasive particle 100must achieve a gross biased orientation before entering and passingthrough one of the slots, with the walls further serving to support theabrasive particle in the biased orientation as shown for example inFIGS. 5 and 6D. While the slot width W_(S) (FIG. 3) can closelyapproximate the maximum thickness T_(P) so as to dictate a more preciseparticle Z_(P) axis and Y_(P) axis rotation orientation of the appliedabrasive particles 100 (i.e., as the slot width W_(S) approaches themaximum thickness T_(P), the range of possible Z_(P) axis and Y_(P) axisrotational orientations the abrasive particle 100 can assume and still“fit” in the slot is reduced), in some embodiments, the slot width W_(S)is greater than the maximum thickness T_(P) for enhanced throughput time(i.e., by providing a larger slot width W_(S), abrasive particles 100can randomly assume a larger range of Z_(P) axis and Y_(P) axisrotational orientations and still enter/pass through one of the slots,thereby making it “easier” for an individual abrasive particle 36 toobtain an appropriate spatial orientation and improving the mass flowrate of the abrasive particles 100 through the distribution tool),approaching, but not exceeding, the particle maximum length and maximumheight L_(P), H_(P). For example, the slot width W_(S) can be 50-75% ofthe maximum height H_(P) (so long as the calculated value is greaterthan the maximum thickness T_(P)). In yet other embodiments, theselected slot width W_(S) is a non-integer factor of the maximumthickness T_(P) (i.e., the slot width W_(S) is not equal to the maximumthickness T_(P), 2T_(P), 3T_(P), etc.) to avoid clogging (e.g., were theslot width W_(S) to be equal to two times the maximum thickness T_(P),two abrasive particles 100 could become aligned side-by-side each otherand then collectively become lodged to the opposing walls of one of theslots). With some embodiments incorporating the alternating heightwalls, a width between an adjacent pair of the taller walls can beselected to be greater than the particle maximum length L_(P) andmaximum height H_(P). With this design criteria, a single abrasiveparticle 100 cannot span two “high” points (e.g., the second ends of anadjacent pair of the taller walls), greatly increasing the mass flow ofthe abrasive particles 100 through the distribution tool.

With the above description in mind various distribution tools aredescribed. FIG. 3 shows a perspective view of a distribution tool 200from a down-web position. The distribution tool 200 is positioned abovea backing 202 which is moving down-web as indicated by an arrow. Thebacking 202 has a first major surface 204 and an opposing second majorsurface 206.

The distribution tool 200 is partitioned into a first section 208 and asecond section 210. Although only two sections and two particle typesare shown in FIG. 3, it should be recognized distribution tools can beconstructed having three or more sections and three or more particletypes according to some embodiments of this disclosure. The firstsection 208 can be disposed up-web of the second section 210. Suchpartition can be accomplished by a transverse wall 212 that extendsgenerally cross-web (in the x-axis direction using the Cartesiancoordinate system provided) across the distribution tool 200. Thedistribution tool 200 includes walls 214 oriented generally to extendup-web/down-web (in the y-axis direction using the Cartesian coordinatesystem provided). The walls 214 can couple to the transverse wall 212.Although the illustrated embodiment utilizes walls 214, otherembodiments contemplate utilizing strings, wires or other types ofmembers that can partition the particles as desired. The walls 214 arespaced apart from one another a width in the cross-web direction (x-axisdirection). Each two of the walls 214 cooperatively define a slot 216therebetween. As discussed above, the dimensions of the slot (slot widthW_(S), slot height H_(S), and slot length L_(S)) are defined by the walldimensions and can be selected as a function of expected abrasiveparticle dimensions (maximum length L_(P), maximum height H_(P) andmaximum width W_(P)).

A plurality of abrasive particles 100 and 100A are provided to thedistribution tool as part of the systems and methods described. Theplurality of abrasive particles 100 and 100A can comprise a firstplurality of abrasive particles 100 of a first type and a secondplurality of abrasive particles 100A of a second type that differs fromthe first type. The second plurality of abrasive particles 100A are showgenerically as diamond shapes in FIG. 3 to illustrated the differencebetween the first plurality of abrasive particles 100 and the secondplurality of abrasive particles 100A. The difference between the firstplurality of abrasive particles 100 and the second plurality of abrasiveparticles 100A can comprise any geometric or weight difference, forexample. Thus, the first plurality of abrasive particles 100 can differfrom the second plurality of abrasive particles 100A in one or more ofparticle shape, particle size (e.g., one or more of maximum lengthL_(P), maximum height H_(P) and maximum width W_(P) differs), averageparticle weight, chemistry, shaped v. unshaped (e.g., triangular v.crushed), or the like. In some cases, the second plurality of abrasiveparticles may not even comprise an abrasive particle but can be a filleror other material for example.

The first plurality of abrasive particles 100 are provided to the firstsection 208 from a source (recall source 40A of FIG. 1). Respective onesof the plurality of abrasive particles 100 fall through respective slots216 to the backing 202 as indicated by arrows. In so doing, the grossbiased rotational orientation and a segregated disposition of the firstplurality of abrasive particles 100 is achieved as discussed above.

The first plurality of abrasive particles 100 then travel down-web withrespect to the distribution tool 200 with movement of the backing 202.Conversely, in other embodiments (e.g., FIG. 7) the distribution toolcan be moved relative to the backing to achieve a similar affect. Itshould be noted that movement of either the backing 202 or thedistribution tool 200 need not be strictly limited to a straight linearpath such as in the down-web direction (y-axis direction) but can alsovaried in several directions (e.g., also in the cross-web direction(x-axis direction) as desired. This would allow for rows of particlesthat have an intentional variation in both the down-web and thecross-web direction (e.g., a sinusoidal shape for example).

In passing through the distribution tool 200 and under the distributiontool 200 on the backing 202, the first plurality of abrasive particles100 are segregated from one another by walls 214 in the cross-webdirection. In traveling down-web the first plurality of abrasiveparticles 100 eventually leave the first section 208 and enter thesecond section 210 of the distribution tool 200.

The second plurality of abrasive particles 100A are provided to thesecond section 210 from a second source (recall source 40B of FIG. 1).Respective ones of the plurality of abrasive particles 100A fall throughrespective slots 216 to the backing 202 as indicated by arrows. In sodoing, the gross biased rotational orientation and a segregateddisposition of the second plurality of abrasive particles 100A can beachieved as discussed above in some embodiments. However, in embodimentswhere the first plurality of abrasive particles 100 and/or the secondplurality of abrasive particles 100A are of sufficiently small geometricshape the gross biased rotational orientation is not achieved. Rather,the segregated disposition of the first plurality of abrasive particles100 and/or the second plurality of abrasive particles 100A is solelyachieved by the walls 212 as desired.

The second plurality of abrasive particles 100A join the first pluralityof abrasive particles 100 on the backing 202 at least partially withinthe distribution tool 200. As shown in FIG. 3, the second plurality ofabrasive particles 100A can be randomly disposed in the down-webdirection (y-axis direction) relative to the first plurality of abrasiveparticles 100. For example, in some cases the second plurality ofabrasive particles 100A can be interposed with the first plurality ofabrasive particles 100 in the down-web direction. In other cases,several of the second plurality of abrasive particles 100A can bedisposed adjacent one another without one of the first plurality ofabrasive particles 100 interposed therebetween. It should be noted thatin some embodiments, the second plurality of abrasive particles 100A canoccupy a same up-web/down-web position (y-axis position) as the firstplurality of abrasive particles 100 but can differ in disposition in thecross-web direction (x-axis direction).

In passing through the distribution tool 200 and under the distributiontool 200 on the backing 202, the second plurality of abrasive particles100A are segregated from one another by walls 214 in the cross-webdirection. In traveling down-web the second plurality of abrasiveparticles 100 and the first plurality of abrasive particles 100 caneventually leave the distribution tool 210 for further processing asshow in FIG. 1.

FIG. 4 shows a distribution tool 300 that can be used according to themethods and systems described herein. The distribution tool 300 isviewed from a down-web position. The distribution tool 300 is positionedabove the backing 202 which is moving down-web as indicated by an arrow.The backing 202 has the first major surface 204 and an opposing secondmajor surface 206 as previously described.

A plurality of abrasive particles 100 and 100A are provided to thedistribution tool 300 as part of the systems and methods described. Theplurality of abrasive particles 100 and 100A can comprise the firstplurality of abrasive particles 100 of a first type and the secondplurality of abrasive particles 100A of a second type that differs fromthe first type in the manner previously described. In some cases, thesecond plurality of abrasive particles may not even comprise an abrasiveparticle but can be a filler or other material for example.

The distribution tool 300 has a construction very similar to that of thedistribution tool 200 previously described. Thus, the distribution tool300 can include a first section 308, a second section 310, a transversewall 312, walls 314 and slots 316 as previously described. A majordifference between the distribution device 300 and the distributiondevice 200 is that the distribution device 300 includes baffles 318A and318B.

The baffles 318A are disposed in the first section 308 atop certain ofthe walls 314. The baffles 318A span slots 316 so as to block certaindesired slots 316 (indicated as slots 316A, 316C, 316E and 316G) suchthat the first plurality of particles 100 cannot enter these slots 316A,316C, 316E and 316G). Thus, the first plurality of particles 100 onlypass through slots 316B, 316D, and 316F to the backing 202. Althoughshown as an alternating pattern (i.e. baffle 318A, open slot 316B,baffle 318A, open slot 316D, etc.) in the cross-web direction (x-axisdirection) in FIG. 4, according to other embodiments any desiredarrangement of baffles to open slots can be utilized.

The baffles 318B are alternated with baffles 318A in the cross-webdirection (x-axis direction) and are offset therefrom in the down-webdirection (y-axis direction). More particularly, the baffles 318B aredisposed in the second section 310 atop certain of the walls 314. Thebaffles 318B span slots 316 so as to block certain desired slots 316(indicated as slots 316B, 316D, and 316F) such that the second pluralityof particles 100A cannot enter these slots 316B, 316D, and 316F). Thus,the second plurality of particles 100A only pass through slots 316A,316C, 314E and 316G to the backing 202. Although shown as an alternatingpattern (i.e. open slot 316A, baffle 318A, open slot 316C, baffle 318A,open slot 316F) in the cross-web direction (x-axis direction) in FIG. 4,according to other embodiments any desired arrangement of baffles toopen slots can be utilized.

In passing through the distribution tool 300 and under the distributiontool 300 on the backing 202, the first plurality of abrasive particles100 are segregated into certain cross-web locations on the backing 202by the walls 314, slots 316 and baffles 318A as illustrated. Intraveling down-web, the first plurality of abrasive particles 100eventually leave the first section 308 and enter the second section 310of the distribution tool 300 where the first plurality of abrasiveparticles 100 are segregated from the second plurality of abrasiveparticles 100A in the cross-web direction by walls 314 and baffles 318B.In this manner a desired spacing (cross-web distance) between the firstplurality of abrasive particles 100 and the second plurality of abrasiveparticles 100A can be achieved. As shown in the embodiment of FIG. 4, adistinct row of the first plurality of abrasive particles 100 can extendin the down-web direction and can alternate and/or be disposed adistance from a row of the second plurality of abrasive particles 100A.

As shown in FIG. 4A, the first plurality of abrasive particles 100 areprovided to the first section 308 such as a first source (recall source40A of FIG. 1). The second plurality of abrasive particles 100A areprovided to the second section 310 from a second source (recall source40B of FIG. 1). Transverse wall 312 (FIG. 4) is removed in FIG. 4A.Respective ones of the first plurality of abrasive particles 100 and thesecond plurality of abrasive particles 100A fall through respectiveslots 316 to the backing 202 as dictated by the baffles (only baffle318A is shown). In falling through the respective slots 316, the grossbiased rotational orientation and a segregated disposition of the firstplurality of abrasive particles 100 and the second plurality of abrasiveparticles 100A can be achieved as discussed above in some embodiments.However, in embodiments where the one of the first plurality of abrasiveparticles 100 and/or the second plurality of abrasive particles 100A areof sufficiently small geometric shape the gross biased rotationalorientation is not achieved. Rather, the segregated disposition of thesecond plurality of abrasive particles 100A (within a cross-web rangedictated by the walls 314) from the first plurality of abrasiveparticles 100 can be achieved. Similarly, segregated disposition of thefirst plurality of abrasive particles 100 (within a cross-web rangedictated by the walls 314) from the second plurality of abrasiveparticles 100A can be achieved.

FIG. 5 is a cross-section of the distribution tool 300 of FIGS. 4 and4A. FIGS. 5 and 6A-6D are provided to further illustrate a method ofmanufacturing including how the first plurality of abrasive particles100 are disposed on the backing 202 by passing through the distributiontool 300 to achieve the gross biased rotational orientation.

According to FIG. 5, the distribution tool 300 is located immediatelyadjacent (e.g., slight above by a distance described in greater detailbelow) the backing 202. The elongated walls 314 (and thus the slots 316)are substantially aligned (e.g., within 10% of a truly alignedrelationship) with the up-web/down-web direction.

During use, the first plurality abrasive particles 100 is loaded ontothe distribution tool 300 at the first section 308. Individual ones ofthe first plurality of abrasive particles 100 will enter a respectiveone of the slots 316 as dictated by the baffles 318A and only uponachieving a gross spatial orientation dictated by dimensions of theslots 316. For example, a first abrasive particle 101 a in FIG. 5 isspatially oriented so as to enter the slot 316, whereas a spatialorientation of a second abrasive particle 101 b prevents entry into anyof the slots 316.

As a point of reference, loading of the supply can include pouring orfunneling (e.g., via vibratory feeder, belt driven drop coater, etc.) alarge number of the abrasive particles 100 on to the distribution tool300 under the force of gravity, with individual ones of the so-loadedabrasive particles 100 randomly assuming any spatial orientation. As theindividual abrasive particles 100 repeatedly contact one or more of thewalls 314, they deflect and assume a new spatial orientation, eventuallybecoming generally aligned with and assuming a spatial orientationappropriate for entering one of the slots 316 that is not blocked by oneof the baffles 318A. Although baffles 318A are illustrated as flat inthe z-axis direction in FIG. 5, according to other embodiments they mayhave a varying z-axis height to facilitate the abrasive particles 100 inentering the slots 316.

To assist in promoting the gross alignment and orientation, thedistribution tool 300 (or any of the distribution device or toolsdiscussed herein) can include a vibration device connected to thedistribution tool 300, causing the abrasive particles 100 to vibratearound on surfaces of the distribution tool 100 until they obtain asuitable orientation and fall through one of the slots 316. Whereprovided, the direction of vibration can be in a plane of the walls 314;random vibration may reduce the mass flow rate of the abrasive particles100 through the distribution tool 300 and may knock many of the appliedabrasive particles 100 over as they exit the distribution tool 100.

In some embodiments in which the edges of the walls 314 can be arealternately offset (in the height direction) from one another, such thatabrasive particles 100 are naturally encouraged to assume the spatialorientation appropriate for entering one of the slots 316 therebyreducing “bridging” of the abrasive particles 100 at the top of thedistribution tool 300.

Once a necessary spatial orientation is achieved, the so-arrangedabrasive particle 100 passes through the corresponding slot 316, fallson to the backing 202 and is at least partially bonded thereto (e.g.,the first abrasive particle 101 identified in FIG. 5). The lower side ofthe distribution tool 300 is spaced from the backing 202 by a gap G thatis less than a maximum dimension(s) of the abrasive particles 100. Thus,a portion of the abrasive particles 101 a even when affixed to anddisposed on the backing 202 remains within the corresponding slot 316.

As shown in FIGS. 6B-6C, the backing 202 is driven relative to thedistribution tool 300 in the down-web direction (y-axis direction), suchthat the applied abrasive particles 101 a and 101 b travel relative tothe distribution tool 300 with movement of the backing 202.

During this movement, one or more of the walls 314 of the distributiontool 300 can support the applied abrasive particles as shown in FIG. 5.This can prevent the applied abrasive particles 101 a from experiencingan overt change in spatial orientation (e.g., the applied abrasiveparticles 101 a are preventing from overtly tipping or rotating in adirection perpendicular to the corresponding slot 316).

FIG. 6B reflects that as the abrasive particles 100 initially drop orfall along one of the slots 316, rotational orientation about theparticle X_(P) axis (FIGS. 2A-2C) is effectively unconstrained, suchthat the abrasive particle 100 can initially contact the backing 202 ata wide range of particle X_(P) axis rotational orientations. Once incontact with the backing 202, the abrasive particle 100 will naturallyseek a stable orientation as it traverses the distribution tool 300while being pulled along by the backing 202 in the down-web direction(y-axis direction).

Upon traveling beyond the first section of the distribution tool 300 asillustrated in FIG. 6C, the applied abrasive particles 101 a and 101 b(of two different types and in two different slots 316) are now morefirmly bonded to the backing 202 and maintain the gross biasedorientation and alignment dictated by the distribution tool 300. In somecases, the systems and methods of the present disclosure include theapplied abrasive particles 101 a and 101 b being in simultaneously incontact with the backing 202 and in some cases one (or more) of thewalls 314 of the distribution tool 300 over a dwell period beneath thedistribution tool 300.

As shown in FIG. 6A, an abrasive article manufacturer may prefer thatthe abrasive particle 100 be applied to and retained at the first majorsurface 204 of the backing 202 in an “upright” position (i.e., one ofthe side faces 106-110 of the abrasive particle 100 bears against or isembedded into the first major surface 204, as compared to a non-uprightorientation in which one of the particle major faces (e.g., 102) is atthe first major surface 204).

The end view of FIG. 6D reflects that the gross biased orientationeffectuated by the distribution tool 300 limits the z-axis rotationalorientation (i.e., the applied particle's angular rotation about az-axis passing through the particle and through the backing 202 to whichthe particle 100 is attached). Such z-axis rotational orientation isexhibited by two of the attached abrasive particles 101 c and 101 d to aprescribed range, although the z-axis rotational orientations will notbe identical for all abrasive particles 100 and will depend on theparticles individual geometry. Similarly, FIG. 6D shows the gross biasedorientation effectuated by the distribution tool 300 limits the y-axisrotational orientation (i.e., the applied particle's 100 angularrotation about a y-axis passing through the particle 100 and relative tothe backing 202 to which the particle 100 is attached). This isexhibited as a lean of abrasive particle 101 e against the wall 314 withthe arrows and indicated axis “y” in FIG. 6D. The distance dmin in FIG.6D indicates a minimum cross-web distance between the first and secondtypes of particles, which corresponds to a thickness of the wall 314.The distance dmax in FIG. 6D indicates a maximum cross-web distancebetween first and second types of particles which would be reduced bythe diameter of any particle in the region. The distance dmax cancomprise the cross-web distance of a slot according to one example.

Although the walls 314 are shown as oriented at substantiallyperpendicular to the backing 202 in FIG. 6D, in other embodiments thewalls 314 can be disposed at an angle that is not perpendicular. Forexample, the walls 314 can be oriented so as to create an acute anglebetween a face of the wall 314 and the backing 202. This can allow they-axis rotational orientation be imparted to the particle 100 so thatone major surface of the particle 100 could rest at an acute angle withrespect to the backing 202.

The distribution tools of the present disclosure are equally useful withother abrasive article manufacturing systems and methods apart fromthose implicated by FIGS. 1, 3, 4 and 8. For example, the distributiontools of the present disclosure can be utilized to apply abrasiveparticles at a grossly biased orientation that is other than down-web.For example, the distribution tool 400 can be used to apply the firstplurality of abrasive particles and the second plurality of abrasiveparticles as previously discussed and illustrated onto backing webconstructions that have disc or other non-linear shapes. With these andother alternative embodiments, the backing and the distribution tool donot move relative to one another as the abrasive particles are beingapplied (e.g., the backing construction web and the distribution toolboth remain stationary, or the backing construction web and thedistribution tool move in tandem). In FIG. 7, the distribution tool 400(of a similar construction as one of the distribution tool 200 or 300)is utilized to apply the abrasive particles 100 and 100A to a backingweb construction or backing 402. The backing 402 has a disc shape. Theabrasive particles 100 and 100A are initially supplied to thedistribution tool 400, and then applied to a surface of the backing 402in the manner previously described including by passing through slots416. As the abrasive particles 100 and 100A are distributed on to thebacking 402, the distribution tool 400 and the backing 402 can remainstationary relative to another; once, the abrasive particles 100 and100A have been applied, the distribution tool 400 is incrementally moved(e.g., rotated) relative to the backing 402 in a direction representedby the arrow M (and/or vice-versa) until the distribution tool 400 isover a “new” area of the backing 402 for receiving additional ones ofthe abrasive particles 100 and 100A. Alternatively, the distributiontool 400 can be sized and shaped such that as the abrasive particles 100and 100A are being supplied to the distribution tool 400, thedistribution tool 400 can be slowly moved (e.g., rotated) relative tothe backing 402 in the direction M (and/or vice-versa) at a sufficientrate that permits the applied abrasive particles 100 and 100A to passbeyond the channels 416 without experience an overt applied force (i.e.,the applied abrasive particles 36 are not forced to fall over due tocontact with one of the walls).

FIG. 8 shows a distribution tool 500 according to another embodimentthat can be used as part of the abrasive article manufacturing system ormethod. The distribution tool 500 is located immediately adjacent (e.g.,slight above by a distance described previously with regards to priorembodiments) the backing 202. Further, the distribution tool 500 isconfigured and arranged relative to the backing 202 such that the slots516 (referenced generally in FIG. 8) optionally are substantiallyaligned (e.g., within 10% of a truly aligned relationship) with thedown-web direction (y-axis direction). However, other arrangements arealso envisioned, such as the slots 516 being arranged substantiallyperpendicular to the down-web direction.

During use, a supply 502 and 502A (referenced generally) of the abrasiveparticles 100 and 100A is loaded to the distribution tool 500 via asource 504 and 504A, respectively. The distribution tool 500 cancomprise two drums 506 and 506A each having a central bore 562, theaforementioned slots 516 and walls 514. According to one example, thesource 504 and 504A can be akin to a mineral dropper having an outlet(referenced generally) that extends into each central bore 562,respectively. The supply of the abrasive particles 100 and 100A flowsthrough the outlet and into the central bore 562 of each drum 506 and506A, respectively.

Once within the central bore 562, individual ones of the abrasiveparticles 100 and 100A will enter a respective one of the slots 516 forthe respective drum 506 and 506A. In some embodiments, entry of theabrasive particles 100 and/or 100A is possible only upon achieving agross spatial orientation dictated by dimensions of the slots 516 aspreviously discussed.

As a point of reference, loading of the supply can include pouring orfunneling (e.g., via vibratory feeder, belt driven drop coater, etc.) alarge number of the abrasive particles 100 and 100A on to (or into) thedistribution tool 500 under the force of gravity, with individual onesof the so-loaded abrasive particles 100 and 100A randomly assuming anyspatial orientation.

FIG. 8A provides a specific example of portions of the drums 506 and506A illustrated. As shown in FIG. 8A, the slots 516 (indicated as 516for the drum 506 and 516A for the second drum 506A) can be staggeredwith respect to one another in the cross-web direction (x-axisdirection). In particular, the slots 516 of the drum 506 are staggeredwith respect to the slots 516A of the second drum 506A such that thewall 514 of the drum 506 will be disposed up-web of the slot 516A.

FIG. 8B shows passage of the respective first plurality of abrasiveparticles 100 through the drum 506 and the second plurality of abrasiveparticles 100A through the drum 506A. FIGS. 8A and 8B are a simplifiedrepresentation of a portion of the distribution tool 500 with a portionsof the drums 506 and 506A removed such that the first plurality ofabrasive particles 100 (FIG. 8B) in the first slots 516 are visible(with a size highly exaggerated) and the second plurality of abrasiveparticles 100A (FIG. 8B) in the second slots 516A are visible (with asize highly exaggerated).

The first plurality of abrasive particles 100 and the second pluralityof abrasive particles 100A in FIG. 8B is spatially oriented so as toenter the slots 516 and 516A, respectively.

With reference between FIGS. 8A and 8B, as the individual abrasiveparticles 100 and 100A repeatedly contact one or more of the walls 514(ring shaped), they deflect and assume a new spatial orientation,eventually becoming generally aligned with and assuming a spatialorientation appropriate for entering one of the slots 516 and/or 516A.In this regard, as the supply of the abrasive particles 100 and 100Aflows into each drum 506 and 506A, each drum 506 and 506A is rotated(e.g., via a rotation device (not shown)). This rotation (indicated bythe arrow R in FIG. 8) mixes and vibrates, the abrasive particles 100and 100A on surfaces of the drum 506 and 506A until they obtain asuitable orientation and fall through one of the slots 516 and 516A.Regardless, a large number of abrasive particles 100 and 100A can bedisposed within individual one of the slots 516 and 516A at any onepoint in time rather than just the few particles illustrated in FIG. 8B.

Returning to FIG. 8A, the staggered slot 516 and 516A arrangementfacilitates segregation of the first plurality of particles 100 adistance in the cross-web direction (x-axis direction) from the secondplurality of particles 100A in a manner similar to that previouslydescribed in reference to FIGS. 4 and 4A.

FIG. 9 illustrates a distribution tool 600 of similar construction tothat of the distribution tool 500 utilizing drums 606 and 606A,respectively. The embodiment of FIG. 9 differs in that the drum 606A canbe disposed a substantially larger gap G from the backing 202 than thedrum 606. Thus, the second plurality of particles 100A can be droppedfrom a greater distance than the first plurality of particles 100 asillustrated in FIG. 9.

According to another embodiment, the distribution tool can comprise asingle drum rather than the previous two or more drums previouslyillustrated and described. The single drum could have dedicated slotsconfigured for a first abrasive particle and dedicated second slotsconfigured for a second abrasive particle, mineral or filler. Forexample, the single drum can have a double helix creating the twoseparate dedicated slots. The slots could then act as channels for eachof the two abrasive particles. Thus, this embodiment could achieve anoffset cross-web disposition for the different abrasive particle typesusing a single drum.

FIGS. 10A and 10B show abrasive articles that utilize the firstplurality of abrasive particles and the second plurality of abrasiveparticles previously discussed in reference to prior of the FIGURES.

Bearing in mind the particle referencing system previously described inreference to FIGS. 2A-2C, FIG. 10A shows a portion of an abrasivearticle 700 with a first plurality of abrasive particles 702 that areconstrained by a pair of imaginary boundaries 712 a, 714 a, 712 b, 714b, 712 c, 714 c. The distance between the imaginary boundaries 712 a,714 a, 712 b, 714 b, 712 c, 714 c for the first plurality of abrasiveparticles 702 is designated distance d₁. These imaginary boundaries 712a, 714 a, 712 b, 714 b, 712 c, 714 c correspond to regions 716 a, 716 b,716 c, respectively, where the first plurality of abrasive particles 702can be generally be located. As shown in FIG. 10A, as a result of thisconstraint, rows 704 of cross-web (x axis) spaced apart first pluralityof abrasive particles 702 are formed. In some cases, the regions 716 a,716 b, 716 c also represent locations where the first plurality ofabrasive particles 702 are constrained with respect to the z-directionrotational orientation as previously discussed. Such constrain can be toa predetermined angle depending on the geometry of the first pluralityof abrasive particles 702.

Similarly, FIG. 10A shows the abrasive article 700 with a secondplurality of abrasive particles 702A that are constrained by theimaginary boundaries (simplified to be denoted as 714 a and 712 b, 714 band 712 c). Both the first plurality of abrasive particles 702 and thesecond plurality of abrasive particles 702 extend in similar paths toone another with respect to the y-axis but are spaced at least a minimumdistance in the x-axis direction from one another. The minimum distancecan comprise a thickness of one of the walls previously described inreference to the prior distribution tools. The distance between theimaginary boundaries 714 a and 712 b and 714 b and 712 c for the firstplurality of abrasive particles 702A is designated distance d₂. Theseimaginary boundaries 714 a and 712 b and 714 b and 712 c correspond toregions 718 a and 718 b, respectively, where the second plurality ofabrasive particles 702A can be generally be located. As shown in FIG.10A, as a result of this constraint, rows 704A of cross-web (x axis)spaced apart second plurality of abrasive particles 702A are formed.These can be alternated with the rows 704 of the first plurality ofabrasive particles 702 in some embodiments. In some cases (though notthe embodiment of FIG. 10A), the regions 718 a and 718 b also representlocations where the second plurality of abrasive particles 702A areconstrained the z-direction rotational orientation. It should be notedthat the size of the regions 718 a and 718 b can differ from that of theregions 716 a, 716 b, 716 c as the distance d₂ can differ from distanced₁.

It will be recognized that the imaginary boundaries 712 a, 714 a, 712 b,714 b, 712 c, 714 c need not be linear or parallel. That is, theimaginary boundaries 712 a, 714 a, 712 b, 714 b, 712 c, 714 c may be,for example, arcuate, curved, serpentine or irregular do to movement ofthe distribution tool 700 relative the backing or the backing relativeto the distribution tool 700. Thus, the abrasive particles 702 and 702Amay be provided in a variety of patterns including, for example, wavy,sinusoidal, circular or in a random path.

A distance between adjacent of the first plurality of abrasive particles702 can vary randomly along the y-axis. Similarly, a distance d₄ betweenadjacent of the second plurality of abrasive particles 702A can varyrandomly along the y-axis. Thus, the y-axis distance between adjacent ofthe first and second plurality of abrasive particles 702 and 702A is notfixed, and there is no discernable pattern to the arrangement of thefirst and second plurality of abrasive particles 702 and 702A in they-axis direction. However, because the x-axis spacing distance betweenthe first and second plurality of abrasive particles 702 and 702A isconstrained to the aforementioned regions by baffles and walls, etc. thefirst and second plurality of abrasive particles 702 and 702A are spacedmore uniformly in the x-axis direction than the y-axis direction.

Referring to FIG. 10B, there is shown an abrasive article 800 in theform of a circular disc 824. The abrasive disc 824 comprises a backing202 as previously discussed having a first major surface, and a firstplurality of abrasive particles 702 and a second plurality of abrasivearticles 702A as previously discussed with reference to FIG. 10A. Thefirst plurality of abrasive particles 702 and the second plurality ofabrasive articles 702A are secured to the backing 202 via an optionalmake coat (not shown). Imaginary boundaries 812 a, 814 a, 812 b, 814 b,812 c, 814 c define annular paths 826 a, 826 b, 826 c and further defineannular regions 816 a, 816 b, 816 c that generally constrain thelocation of the second plurality of abrasive particles 702A. Similarly,the boundaries 810 and 812 a, 814 a and 812 b, and 814 b and 812 cdefine further annular paths 828 a, 828 b, 828 c and further defineannular regions 818 a, 818 b, 818 c that generally constrain thelocation of the second plurality of abrasive particles 702A.

In the illustrated embodiment, the abrasive disc 824 includes a firstaxis 820 tangent to the annular paths at the location of the firstplurality of abrasive particles 702 and the second plurality of abrasivearticles 702A. The abrasive disc 824 further includes a radial axis 828orthogonal to the tangent axis 820, and a z-axis orthogonal to thetangent axis 820 and the radial axis 828 (the z-axis is not shownextending directly outwardly from the plane of the page). The radialspacing distance d₂ of the regions 818 a, 818 b and 818 c can becontrolled as can the radial spacing distance d₁ of the regions 816 a,816 b and 816 c. The radial spacing distance d₂ can differ from or besubstantially the same as the radial spacing distance.

FIGS. 11-12A provide exemplary embodiments of abrasive articles havingthe first plurality of abrasive particles and the second plurality ofabrasive particles. FIG. 11 shows a first plurality of abrasiveparticles 900 and the second plurality of abrasive particles 900A usedin an abrasive article 901 that also includes a backing 202. The firstplurality of abrasive particles 900 and the second plurality of abrasiveparticles 900A comprise shaped abrasive particles 902 with aconstruction similar to the embodiment previously described in referenceto FIGS. 2A-2C. The first plurality of abrasive particles 900 differfrom the second plurality of abrasive particles 900A in that the sizeand weight of the second plurality of abrasive particles 900A differsfrom the first plurality of abrasive particles 900. As shown in FIG. 11the first plurality of abrasive particles 900 are spaced from the secondplurality of abrasive particles 900A by at least a minimum distancedrain in the x-axis direction (the cross-web direction). Both the firstplurality of abrasive particles 900 and the second plurality of abrasiveparticles 900A extend in similar paths 904 and 904A to one another withrespect to the y-axis. FIG. 11A is a digital image of an abrasivearticle 1000 having similar construction to article 900 of FIG. 11. Thearticle 1000 has shaped abrasive particles of different size.

FIG. 12 shows a first plurality of abrasive particles 1100 and a secondplurality of abrasive particles 1100A used in an abrasive article 1101that also includes the backing 202. The first plurality of abrasiveparticles 1100 comprise shaped abrasive particles 1102 with aconstruction similar to the embodiment previously described in referenceto FIGS. 2A-2C, while the second plurality of abrasive particles 1100Acomprise a non-shaped abrasive. As shown in FIG. 11 the first pluralityof abrasive particles 1100 are spaced from the second plurality ofabrasive particles 1100A by at least a minimum distance d_(min) in thex-axis direction (the cross-web direction). Both the first plurality ofabrasive particles 1100 and the second plurality of abrasive particles1100A extend in similar paths 1104 and 1104A to one another with respectto the y-axis.

FIG. 11A is a digital image of an abrasive article 1200 having abrasiveparticles but also including a non-abrasive material such as a filler1202 that is disposed in the manner and utilizing the systems andmethods described herein.

It has been found that the size (i.e. volume) and weight (i.e. mass) ofthe abrasive particles can impact the degree of z-direction rotationalorientation, and the position or placement of the abrasive particles onthe backing. The impact of the size and weight of the abrasive particlecan be particularly pronounced depending on the particular techniqueused to apply the abrasive particles to the substrate. Accordingly, incertain embodiments, a portion of the abrasive particles may have anaverage volume of at least 2, 3, 5 or 7 cubic millimeters, and may havean average weight of at least about 0.5, 1, 2 or 3 milligrams.

It will be recognized that the abrasive articles according to thepresent disclosure may be converted into, for example, an endless orcontinuous belts, discs (including perforated discs), sheets and/orpads. For belt applications, two free ends of a sheet-like abrasivearticle may be joined together using known methods to form a splicedbelt. In addition, it will be recognized that the make coat may beprovided as a layer across the entire first major surface of theabrasive article, it may be provided on only select regions of the firstmajor surface, or the make coat may be applied directly to the abrasiveparticles prior to affixing the abrasive particles to the backing. Inaddition, the coating weight of the abrasive particles in the variousembodiments described herein may range from at least about 10, 50, 100,500, 1000, 1500 or 2000 grams/square meter (g/m²), to no greater thanabout 4000, 4500 or 5000 g/m².

The abrasive articles described herein can be used for a variety ofabrading applications including, for example, grinding, cutting andmachining applications. In a particular end use application, theabrasive article is a coated abrasive belt used to grind metal, such astitanium or steel.

In order that the invention described herein can be more fullyunderstood, the following examples are set forth. It should beunderstood that these examples are for illustrative purposes only, andare not to be construed as limiting this invention in any manner.

EXAMPLES

Example 1 is a method for making an abrasive article that can comprise:loading a first plurality of abrasive particles and a second pluralityof abrasive particles to a distribution tool, the distribution tool hasa first section for receiving the first plurality of abrasive particlesand a second section for receiving the second plurality of abrasiveparticles, the first section and the second section each including aplurality of walls defining a plurality of slots, each of the pluralityof slots being open to a lower side of the distribution tool, whereinthe first plurality of abrasive particles differ in at least one of asize, an average weight and a shape from the second plurality ofabrasive particles; distributing the first plurality of abrasiveparticles from the first section of the distribution tool on to a firstmajor face of a backing located immediately below the lower side of thedistribution tool and moving relative to the distribution tool; anddistributing the second plurality of abrasive particles from the secondsection of the distribution tool on to the first major face of thebacking located immediately below the lower side of the distributiontool and moving relative to the distribution tool; wherein the firstplurality of abrasive particles and the second plurality of abrasiveparticles when distributed on the backing extend in similar paths in adown-web direction of the backing, the similar paths are limited to across-web range defined by the plurality of walls.

In Example 2, the subject matter of Example 1 optionally includes thefirst section is disposed up-web of the second section such that thestep of distributing the first plurality of abrasive particles initiallydisposes the first plurality of abrasive particles up-web of the secondplurality of abrasive particles on the backing.

In Example 3, the subject matter of any one or more of Examples 1-2optionally include the first section includes one or more first bafflesextending adjacent of the plurality of walls, wherein the first bafflesare configured to block entry of the first plurality of abrasiveparticles into certain of the plurality of slots.

In Example 4, the subject matter of any one or more of Examples 1-3optionally include the second section includes one or more secondbaffles extending between adjacent of the plurality of walls, whereinthe second baffles are configured to block entry of the second pluralityof abrasive particles into certain of the plurality of slots.

In Example 5, the subject matter of Example 4 optionally includes thefirst baffles are staggered in a cross-web direction from the secondbaffles so as to extend between different of the plurality of walls suchthat the first plurality of abrasive particles enter different ones ofthe plurality of slots than the second plurality of abrasive particles.

In Example 6, the subject matter of any one or more of Examples 1-5optionally include distributing the first plurality of abrasiveparticles disposes the first plurality of abrasive particles on a firstdefined region of the backing and distributing the second plurality ofabrasive particles disposes the second plurality of abrasive particleson a second defined region of the backing, and wherein the first definedregion is spaced from the second defined region at least a minimumdistance in a cross-web direction.

In Example 7, the subject matter of any one or more of Examples 1-6optionally include distributing the first plurality of abrasiveparticles disposes the first plurality of abrasive particles on a firstdefined region of the backing and distributing the second plurality ofabrasive particles disposes the second plurality of abrasive particleson the first defined region of the backing, and wherein the firstdefined region is spaced from other defined regions by at least aminimum distance in a cross-web direction.

In Example 8, the subject matter of any one or more of Examples 1-7optionally include distributing at least one of the first plurality ofabrasive particles and the second plurality of abrasive particlesorients at least a majority of at least one of the first plurality ofabrasive particles and the second plurality of abrasive particles inpassing through the plurality of slots.

In Example 9, the subject matter of any one or more of Examples 1-8optionally include the backing includes a make coat along a majorsurface of a backing.

In Example 10, the subject matter of any one or more of Examples 1-9optionally include the first section comprises a first drum and thesecond section comprises a second drum, wherein each of the plurality ofwalls comprise ringed walls of the drum, wherein the first drum and thesecond drum are configured to rotate as the first plurality of abrasiveparticles and the second plurality of abrasive particles as the firstplurality of abrasive particles and the second plurality of abrasiveparticles are passed through respective central portions of the firstdrum and the second drum.

In Example 11, the subject matter of any one or more of Examples 1-10optionally wherein the plurality of walls comprise a plurality of spacedapart members.

Example 12 is a system for making an abrasive article. The system caninclude a distribution tool, a backing, a first plurality of abrasiveparticles and a second plurality of abrasive articles. The distributiontool can include a first section and a second section. Each of the firstsection and second section can have a plurality of walls defining aplurality of slots. Each of the slots can be open to a lower side of thedistribution tool. The backing can be configured to be disposedimmediately adjacent the lower side of the distribution tool. The firstsection can be configured to receive the first plurality of abrasiveparticles and pass the first plurality of abrasive particles through oneor more of the plurality of slots to the backing. The second pluralityof abrasive particles can differ in at least one of a size, an averageweight and a shape from the first plurality of abrasive particles. Thesecond section can be configured to receive the second plurality ofabrasive particles and pass the second plurality of abrasive particlesthrough one or more of the plurality of slots to the backing.

In Example 13, the subject matter of Example 12 optionally includes thedistribution tool is arranged relative to the backing such that for eachof the slots has: a depth that is substantially perpendicular to adown-web direction of the backing, a length that is substantiallyparallel to the down-web direction of the backing, and a width that issubstantially orthogonal to the depth and the length.

In Example 14, the subject matter of any one or more of Examples 12-13optionally wherein the section has one or more first baffles extendingbetween adjacent of the plurality of walls, wherein the first bafflesare configured to block entry of the first plurality of abrasiveparticles into certain of the plurality of slots.

In Example 15, the subject matter of any one or more of Examples 12-14optionally include the second section includes one or more secondbaffles extending between adjacent of the plurality of walls, whereinthe second baffles are configured to block entry of the second pluralityof abrasive particles into certain of the plurality of slots.

In Example 16, the subject matter of Example 15 optionally includes thefirst baffles are staggered in a cross-web direction from the secondbaffles so as to extend between different of the plurality of walls suchthat the first plurality of abrasive particles enter different ones ofthe plurality of slots than the second plurality of abrasive particles.

In Example 17, the subject matter of any one or more of Examples 12-16optionally include the plurality of slots and the plurality of walls areconfigured to orient a majority of at least one of the first pluralityof abrasive particles and the second plurality of abrasive particles inpassing through the plurality of slots.

In Example 18, the subject matter of any one or more of Examples 12-17optionally include the first section comprises a first drum and thesecond section comprises a second drum, wherein each of the plurality ofwalls comprise ringed walls, wherein the first drum and the second drumare configured to rotate as the first plurality of abrasive particlesand the second plurality of abrasive particles as the first plurality ofabrasive particles and the second plurality of abrasive particles arepassed through respective central portions of the first drum and thesecond drum.

In Example 19, the subject matter of Example 18 optionally includes theplurality of slots in the second drum are staggered in a cross-webdirection with respect to the plurality of slots in the first drum suchthat the ringed walls of the first drum interface with and are disposedin a down-web direction of the plurality of slots in the second drum.

In Example 20, the subject matter of any one or more of Examples 12-19optionally include the plurality of walls comprise a plurality of spacedapart members.

What is claimed is:
 1. A method for making an abrasive articlecomprising: loading a first plurality of abrasive particles and a secondplurality of abrasive particles to a distribution tool, the distributiontool has a first section for receiving the first plurality of abrasiveparticles and a second section for receiving the second plurality ofabrasive particles, the first section and the second section eachincluding a plurality of walls defining a plurality of slots, each ofthe plurality of slots being open to a lower side of the distributiontool, wherein the first plurality of abrasive particles differ in atleast one of a size, an average weight, chemistry and a shape from thesecond plurality of abrasive particles; distributing the first pluralityof abrasive particles from the first section of the distribution tool onto a first major face of a resin-coated backing located immediatelybelow the lower side of the distribution tool and moving relative to thedistribution tool; and distributing the second plurality of abrasiveparticles from the second section of the distribution tool on to thefirst major face of the backing located immediately below the lower sideof the distribution tool and moving relative to the distribution tool;wherein the first plurality of abrasive particles and the secondplurality of abrasive particles when distributed on the backing extendin similar paths in a down-web direction of the backing, the similarpaths are limited to a cross-web range defined by the plurality ofwalls.
 2. The method of claim 1, wherein the first section is disposedup-web of the second section such that the step of distributing thefirst plurality of abrasive particles initially disposes the firstplurality of abrasive particles up-web of the second plurality ofabrasive particles on the backing.
 3. The method of claim 1, wherein thefirst section includes one or more first baffles extending adjacent ofthe plurality of walls, wherein the first baffles are configured toblock entry of the first plurality of abrasive particles into certain ofthe plurality of slots.
 4. The method of claim 3, wherein the secondsection includes one or more second baffles extending between adjacentof the plurality of walls, wherein the second baffles are configured toblock entry of the second plurality of abrasive particles into certainof the plurality of slots.
 5. The method of claim 4, wherein the firstbaffles are staggered in a cross-web direction from the second bafflesso as to extend between different of the plurality of walls such thatthe first plurality of abrasive particles enter different ones of theplurality of slots than the second plurality of abrasive particles. 6.The method of claim 1, wherein distributing the first plurality ofabrasive particles disposes the first plurality of abrasive particles ona first defined region of the backing and distributing the secondplurality of abrasive particles disposes the second plurality ofabrasive particles on a second defined region of the backing, andwherein the first defined region is spaced from the second definedregion at least a minimum distance in a cross-web direction.
 7. Themethod of claim 1, wherein distributing the first plurality of abrasiveparticles disposes the first plurality of abrasive particles on a firstdefined region of the backing and distributing the second plurality ofabrasive particles disposes the second plurality of abrasive particleson the first defined region of the backing, and wherein the firstdefined region is spaced from other defined regions by at least aminimum distance in a cross-web direction.
 8. The method of claim 1,wherein distributing at least one of the first plurality of abrasiveparticles and the second plurality of abrasive particles orients atleast a majority of at least one of the first plurality of abrasiveparticles and the second plurality of abrasive particles in passingthrough the plurality of slots.
 9. The method of claim 1, wherein thebacking includes a make coat along a major surface of a backing.
 10. Themethod of claim 1, wherein the first section comprises a first drum andthe second section comprises a second drum, wherein each of theplurality of walls comprise ringed walls of the drum, wherein the firstdrum and the second drum are configured to rotate as the first pluralityof abrasive particles and the second plurality of abrasive particles arepassed through respective central portions of the first drum and thesecond drum.
 11. The method of claim 1, wherein the plurality of wallscomprise a plurality of spaced apart members.